1. Field of the Invention
The present invention relates to a method for manufacturing a printed wiring board, and more specifically relates to a method for manufacturing a printed wiring board that is preferably used for a package substrate for mounting an IC chip.
2. Discussion of the Background
A solder bump is used for electrically wiring a package substrate and an IC chip. The solder bump is formed through the following processes:
(1) A process to print flux on a joint pad formed on the package substrate.
(2) A process to mount a solder ball on the joint pad upon which flux is printed.
(3) A process to form a solder bump from the solder ball by reflowing.
After forming the solder bump on the package substrate, the IC chip is placed on the solder bump, the solder bump and the pad (terminal) of the IC chip are joined together by reflowing, and the IC chip is mounted on the package substrate. In the abovementioned processes to mount a solder ball on a joint pad, a print technology is used, for example by concomitantly using a mask for aligning a ball and a squeegee as shown in Japanese Unexamined Patent Application Publication No. 2001-267731